Adsorption capacity of Cadmium (Cd) from wastewater using corn cob / Melvina Maureen Baja

In the developing world, environmental pollution is becoming a global problem and concern that is caused by the presence of toxic materials such as cadmium. The research aimed was to use low-cost adsorbent such as corn cob wastes in the treatment of industrial wastewater to remove cadmium efficiently. In this research, the parameters of adsorbent dosage, pH of the aqueous solution and different initial metal concentrations were also observed as the factors for the binding of cadmium metal ions at the surface sites of the adsorbent which was the corn cob. To compare the efficiency of the removal using corn cob, it was divided into two samples. One of the samples was treated with 10% hydrochloric acid. The chemical treatment using hydrochloric acid increased the oxygen content of the adsorbent. This treatment encourages cellulose hydrolysis of adsorbent that creates more reactive sites of the adsorbent. Overall, adsorption tests showed that the treated corn with the treatment of the hydrochloric acid resulted in a more efficient process in the removal of cadmium rather than untreated corn cob. The research showed that the removal of cadmium could be achieved at dosage of 3 g/L of treated corn cob (99.43%) and 7 g/L of untreated corn cob (26.47%). For initial metal concentrations, the highest removal efficiency for treated corn cob was at 60 ppm (99.40%) and 20 ppm (50.30%) for untreated corn cob. Besides, treated corn cob was removed at optimum pH 6 at removal efficiency of 76.38% and untreated con cob removed at optimum pH 8 at removal efficiency of 96.58%. The maximum adsorption capacity for cadmium was at 3.31 mg/g. Then, correlation coefficient (R²) of Langmuir was 0.87 and Freundlich was 0.63. Hence, Langmuir isotherm model was better and suited for this research.